Offset printing ink



Patented Jan. 29, 1935 Charles P. Shaw, Detroit, -'Mich assignor to Detroit Moulding CorporatiomDetroit, Mich.

No Drawing.

pplication July 28,1933,- Serial No. 682,028. I

I 5 Claims. '(01. 134-35 The main objects ofmy invention are:

.First, to provide an improveduink for offset printing and more especially for the offset printing of woodgrainefiects in relief.

Second, to. provide a printing ink of this character, which is composed of commercially availableofiset printing ink and a thinner containing readily available ingredients. 7

Third, to'provide offset printingink of this character, which lays down perfectly on the printing plate yet which isnotsothin as to fill up therhalfetoneiplategr Objects relating to details and economies of my invention will appear from the description to follow. The invention is defined and pointed out in the claims.

The printing plate is made planographic by the half-tone process with the design in relief. This is inked by a suitable machine or apparatus or by passing an ink roller over the plate, the ink not being forced down into the recesses, but remaining on the relief or high parts of the plate. A rubber or composition transfer roller is then run over the plate and the design transferred to the panel or object to be ornamented.

In this method of ofiset printing, with surface printing plates as distinguished from intaglio plates, especially with regard to decorating garnish moldings, the method of or agent for producing the ofiset printing ink is of prime importance. The thinner the ink with a sufiicient color, the better the print. Thinned ink readily lifts from the plate and readily releases from the printing roll. The ink must lay down perfectly and yet not be so thin as to fill up the printing plate.

Oil added to the ink will allow it to release from the printing roll, but if used alone makes the ink too thin, fills up the plate and greatly cuts the color of the print. Greasy compounds aid in making the ink lay down and do not cut the color. However, a large amount of such compounds are required for satisfactory results, and further, there is a tendency for them to slur the printing.

I provide a thinner which combines the advantages of oil and greasy compounds, but which eliminates their disadvantages. I add to the offset printing ink a thinner containing the following ingredients by weight:

Castor oil 1.8 oz. 15.9% Colorless 00 Litho varnish 2.5 oz. 22.1% Stearine 3.0 oz. 26.6% Turp n 4.0 oz. 35.4%

ing ink may be used with my thinner, I prefer, to use offsetprinting ink, containing by weight pigment=35%- to 40% and vehicle 65% to The pigment may be carbon black and the vehicle a heavy bodied linseed oil with a'drier of the rosin type. Offset printing ink of this character may be readily bought or it may be duplicated by. any ink manufacturer having facilities for grinding in pigments. Inthe case of black ink the weightof thepigment is about 35% and the ve-' male In the case of brown ink, the pig-k ment runs up to 40% and the vehicle 60%; ,The vehicle itself is from 25% to 30% of the total weight, heavy bodied linseed oil, and 35% of the total weight, varnish.

Summarizing the analysis of the offset printing ink:

Black a Brown Percent Perce'nt Linseed oil 30 25 Varnish 35 35 Pigmen 35 40 While the ratio of my thinner or reducing agent to the offset printing ink will vary with difierent printing conditions, nevertheless I prefer to use 14 parts by weight of my thinner to 86 parts by weight of the offset printing ink.

This preferred ratio of thinner to ofiset printing ink results in an ink which is of such character that a sufiicient quantity thereof is held on the high point or design of the relief printing plate so that an effective transfer is made possible and that very good results are produced.

When the black ink is mixed according to the foregoing description, it comprises in composition by weight the ingredients as follows:

Per Per cent cent Thinner 14 Castor oil .14X15.9 2.2 Varnish .14x22.1 3.1 stearine, .14x26.6 3.7 Turpentine .14x35.4 5.0 Offset printing ink..' 86

Linseed oil .86X30 25.8 Varnish .86x35 30.1 Pigment .86x35 30.1

Total 100.0

The combined varnish content'is thus 33.2% in the above composition.

In the brown ink, the pigment comprises 34.4% of the whole mixture, and the linseed oil 21.5%.

My ink is especially useful in the ornamenting of metal with imitation wood graining. The plate is prepared from a photograph by the half-tone process and with the graining design in relief.

The plate is inked with my special ink by passing an inking roller over the plate, the ink not being forced down into the recesses; but remain;- ing on. the relief or high parts of .theuprinting plate. A pick-up or transfer roller is then run over the inked plate and the graining design trans,- ferred to the panel or surface to be ornamented,

The character of my special ink issuch that it is held on the relief or high partof the'plat e without filling the same and readilyv releases frofni the transfer or printing roll and theplate. My thinner produces these advantageswitl'ioutcutting the color of the offset printing ink and without slurring the printing. These characteristics? oifset 2. An ink comprising in composition oflset printing ink containing by weight: linseed oil; .35 va1 nish;;and black pigment; and a thinner iontainins'l'by fie'iaflt 18.9 mister oil. 22.1% Colorless 00 Litho varnish, 26.6% stearine; and 35.4% turpentine; 14 parts by weight of thinner being added to 86 parts by weight of 011- set pnnungmk.

3; An ink of thelc l aracter set forth, comprisingi jeomppsitiorrpfiset printing ink containing by weight 35% to pigment and 65% to vehiqle thevElifcle consisting of varnish and linseed oil, and a thinner or reducing agent contain- -ing.-rby .v eight substantially 16% castor oil, 22%

varnish, 27% stearine and 35% turpentine, substantially 71% by weight '1 st am -2 reducing gentybein -n ixe'd imnms psmw weight of the-oflset ink;

4. An ink of t'ne-charaetewset i'crtmedmprming in compositicinby weight substantially :=30 1% pigment, :2'5287; linseed brr sam varnish, a;2%-

casto'r'oil, "3'.-7%"s'te'arine,' and snow-turpentine;

5. An ink of tnechsi-seter st forth; compris ng in composition "by weight I substantially: i 343% pigment, -2 :s imseed on; 3.2 9; varnish;- 252% Castor an, -3:;7%:stearine, and 5.0%

, omRms m-smw; 

